1. Technical Field
The present invention relates to a semiconductor device and a method of manufacturing the same.
2. Related Art
Semiconductor device having a semiconductor chip, and an encapsulation resin which covers and encapsulates the semiconductor chip, is referred to as resin-encapsulated semiconductor device.
FIG. 17 is a front elevation illustrating a resin-encapsulated semiconductor device 101. As illustrated in FIG. 17, resin-encapsulated semiconductor device 101 is configured to have a semiconductor chip embedded in an encapsulation resin 103.
In this sort of semiconductor device, a problem may arise in that adhesiveness between the semiconductor chip and the encapsulation resin may degrade.
One possible cause for the degraded adhesiveness is ascribable to tensile stress applied in the direction of drawing the semiconductor chip and the encapsulation resin apart from each other, due to difference in thermal expansion coefficient therebetween. The stress generates typically due to heat applied to a semiconductor device when it is mounted by soldering onto a substrate of electric appliances and so forth, self-heating of the semiconductor device during operation, changes in the ambient temperature, and so forth.
There is known a technique of providing a countermeasure for the degradation in the adhesiveness between the semiconductor chip and the encapsulation resin, such as disclosed in Japanese Laid-Open Patent Publication No. H06-163755.
In the technique disclosed in Japanese Laid-Open Patent Publication No. H06-163755, a surface-textured component having a surface texture formed on the surface thereof is provided on a semiconductor chip, and resin encapsulation is provided thereover. Since the semiconductor chip and the encapsulation resin are tightly bonded while placing the surface-textured component in between, by virtue of the enlarged contact area between the surface-textured component and the encapsulation resin, so that the adhesiveness between the semiconductor chip and the encapsulation resin improves. Japanese Laid-Open Patent Publication No. H6-163755 additionally describes that the adhesiveness may be improved also by configuring the surface-textured component using an organic coverage resin such as polyimide.
However, the present inventors have found the following problem. FIG. 18 is a front elevation illustrating a state of a semiconductor device 101 warped due to the stress. FIG. 19 is a front elevation illustrating the resin-encapsulated semiconductor device 101 illustrated in FIG. 18, in a state having an encapsulation resin 103 removed therefrom. As illustrated in FIG. 19, there is a semiconductor chip 102 having been embedded in the encapsulation resin 103. The semiconductor chip 102 is disposed on a lead frame 104 having leads 5.
The resin-encapsulated semiconductor device 101 may occasionally warp, upon being applied with stress, as illustrated in FIG. 18 and FIG. 19. The warping may raise tensile stress in the direction of drawing the semiconductor chip 102 and the encapsulation resin 103 apart from each other. In other words, a stress generates in the direction normal to the surface of the semiconductor chip 102.
However, the surface-textured component disclosed in Japanese Laid-Open Patent Publication No. H6-163755 merely has recesses formed vertically to the surface of the semiconductor chip, or formed so as to widen themselves towards the opening end. Accordingly, a problem still remains in that the semiconductor chip, applied with the stress in the direction normal to the surface thereof, may cause degradation in the adhesiveness between the encapsulation resin and the recesses, and may consequently cause degradation in the adhesiveness between the encapsulation resin and the semiconductor chip. In conclusion, the technique disclosed in the patent publication is not sufficient in the effect of enhancing the adhesiveness between the semiconductor chip and the encapsulation resin.